One area of research beneficial to machine automation concerns automatic determination of a material, such as determination of the properties of the material or identification and/or discrimination of the material, particularly without contact to the material. For example, in robotic assembly or sorting plants, it can be important to identify objects or parts by optical means based on their material properties for assembling or sorting purposes.
In this context, it has been considered to measure statistics of a speckle pattern, to assist in a non-contact estimation of properties of a material or identification thereof. A speckle pattern results from interference of light waves scattered by a material when illuminated by a light source (such as a laser) with controlled coherence properties.